Integrated circuits commonly require buffer circuits which can operate at a low supply voltage. A common difficulty in the past has been that when the battery which supplies power to the integrated circuit nears the end of its useful life, the battery voltage drops substantially. When this occurs, one or more stages of the buffer circuit may become saturated. When a stage becomes saturated, its gain falls drastically; its input bias current requirement increases, and in general the performance of the stage deteriorates enormously. The circuit ceases to perform adequately when one or more of its stages become saturated.